Crosslinkable composition crosslinkable with a latent base catalyst

ABSTRACT

The present invention relates to a crosslinkable polymer composition comprising reactive components A and B each comprising at least 2 reactive groups wherein the at least 2 reactive groups of component A are acidic protons (C—H) in activated methylene or methine groups and the at least 2 reactive groups of component B are activated unsaturated groups (C═C) to achieve crosslinking by Real Michael Addition (RMA), wherein the component A is a malonate containing component and wherein components A and B react on drying of the crosslinkable polymer composition by deblocking of latent base catalyst C by evaporation of carbon dioxide, which latent base crosslinking catalyst, is a substituted carbonate salt according to formula 1 
                         
wherein X +  represents a non acidic cation and wherein R is hydrogen, alkyl, aryl or aralkyl group.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a US National Stage under 35 USC 371 ofinternational application number PCT/EP2011/055464 filed on Apr. 7, 2011and claims priority from EP application number 10159253.3 filed on Apr.7, 2010, the contents of both applications are hereby incorporated byreference in their entirety.

SUMMARY OF THE INVENTION

The present invention relates to a crosslinkable composition comprisingat least one crosslinkable component and a latent base crosslinkingcatalyst which, which crosslinkable composition preferably has a solidscontent of at least 55 wt % (dry weight after crosslinking relative tothe total weight of the crosslinking composition). The invention relatesin particular to a composition crosslinkable by Real Michael Addition(RMA) reaction wherein a component with at least 2 activated unsaturatedgroups and a component with at least 2 acidic protons C—H in activatedmethylene or methine groups react and crosslink to each other in thepresence of a strong base catalyst. The invention further relates to acoating composition comprising the crosslinkable composition accordingto the invention, a novel catalyst composition and to the use of saidcatalyst composition according to the invention as a latent basecrosslinking catalyst in coating compositions, preferably in RMAcrosslinkable compositions.

The crosslinkable composition is a 2-K system, which implies that thecrosslinking catalyst is added to and mixed with the crosslinkablecomponents shortly before use. From the moment of mixing, thecrosslinking composition is potentially reactive and may start tocrosslink. Such crosslinking compositions can be used only relativelyshortly before the extent of viscosity build-up is such that thecomposition can no longer be used well. This effective use time iscalled the potlife. A latent crosslinking catalyst is used to increasethis potlife, while allowing fast drying. A latent catalyst becomesactive predominantly only when the composition is applied, for exampleas a coating. High solids systems are preferred or required by law toreduce environmental burden, and/or exposure of the painter to harmfulsolvent vapours.

A central challenge in developing coating systems, especially those thatare cured at low to moderate temperatures, is achieving a good balancebetween on one hand rapid crosslinking during application (also referredto as “curing” or “drying”) and on the other hand maintaining long potlives, i.e. the ability to work with the paint without problems for areasonable amount of time after preparation, at least an hour, butpreferably much more. For high solids systems containing less solvent toevaporate upon application, this challenge is significantly greater thanfor low or medium solids systems containing more volatile solvent.Coatings for applications in decorative, vehicle refinish, metal,plastic, marine or protective coatings e.g. require several hours ofpotlife enabling the applicator to bring the paint composition on asubstrate in a well-controlled manner. The viscosity and low solventcontent requirements for high solids systems force the resin designer toselect resins of lower molecular weight and/or lower glass transitiontemperatures that will require more reaction with a crosslinker to raisethe Tg of the network to levels corresponding to a dry film, in the caseof high solids paints. The lower amount of solvent used will create less“physical drying” effects of the film (physical hardening/reducedplastization due to the loss of solvent) than in paints using morevolatile solvents, and also, the increase of the reaction rate goingfrom paint to applied coating is less, because the increase ofconcentration of the reactive groups through the loss of solvent is lesshelpful. All these phenomena add to the problem that for high solidssystems, a combination of fast drying and long pot life is verydifficult to achieve, and much more so than in the case of medium or lowsolids systems.

PRIOR ART

The above described problem has been addressed by Noomen in Progress inOrganic Coatings 32 (1997) 137-14 describing the use of latent basecatalysed Michael addition as crosslinking reaction for high-solidspolymer coating compositions of low VOC. Noomen describes severalexamples of crosslinking catalysts with the required basicity, forexample the amidine types (such as tetra-methyl-guanidine)1,5-diazabicyclo(4,3,0)non-5-ene (DBN),1,8-diazabicyclo(5,4,0)undec-7-ene (DBN), tetra-butylammonium fluorideor in situ formed catalyst from a tertiary amine (like1,4-diazabicyclo[2.2.2]octane: DABCO) with epoxy. Although such priorart catalysts might show quite acceptable curing behaviour in the RMAfilms, the short potlifes are too limited to get acceptable applicationtimes for rolling, brushing and spraying of the coatings, or the dryingrate at lower curing temperatures is too low.

Noomen further describes that, although the film properties (such asdurability when using malonate polyesters) looked promising, there werestill severe shortcomings with this coating composition, in particularin the field of high solids coatings, because the curing under ambientand forced drying conditions revealed inhibition, speculatively assignedto the interaction of the carbon dioxide from the air with the strongbase resulting in a tacky coating surface or inhibition by theinteraction with the acidic groups of the substrate resulting in a lowdegree of cure or a minor adhesion. This was overcome by increasing theamount of catalyst but this resulted in a too short, unacceptablepotlife, especially when using high solid formulations and in lowtemperature applications such as clear coats car refinishing, pigmentedtopcoats for marine, protective and aircraft, wood coatings, etc.Another problem was often the yellowing of the coating inducedespecially under stoving conditions.

EP0448154 (also from Noomen) describes to use certain carboxylic acidsas a blocking agent for a strong basic catalyst. Although a longerpotlife can be achieved, the basic catalyst with carboxylic acids asdescribed in EP448514 provides an insufficient dust- and touch-dryingbehaviour and a low through-drying especially at ambient conditions. Theprior art catalyst does not provide workable potlifes when inhibitionproblems are to be avoided and does not provide fast free-to-handlecoatings, in particular for high solid coatings. Furthermore, deblockingof the catalyst blocked with e.g. carboxylic acids was only applicableat high temperatures.

Therefore there is still a need for crosslinkable compositions having ahigh solid content comprising crosslinkable components, preferably RMAcrosslinkable polymers, and a latent base crosslinking catalyst thatyield a good potlife/drying balance, in particular a workable potlifeand a good drying behaviour also at lower temperatures in coatingcompositions.

There is also a desire for crosslinkable compositions comprising acatalyst that can be simply cured in ambient conditions as opposed tofor example compositions comprising photo-latent amine catalysts, knownfrom T. Jung et al Farbe and Lacke October 2003. Such photo-latent aminecatalysts that do generate a strong base on UV radiation, are notsuitable for coating more complex irregular substrates where parts ofthe surfaces are not reachable with UV or visible light.

According to the invention there is provided a crosslinkable compositioncomprising reactive components A and B each comprising at least 2reactive groups wherein the at least 2 reactive groups of component Aare acidic protons (C—H) in activated methylene or methine groups andthe at least 2 reactive groups of component B are activated unsaturatedgroups (C═C) to achieve crosslinking by Real Michael Addition (RMA)wherein the component A is a malonate containing component and whereincomponents A and B react upon deblocking of latent base catalyst C byevaporation of carbon dioxide, which latent base crosslinking catalystis a substituted carbonate salt according to formula 1

wherein X⁺ represents a non acidic cation and wherein R is hydrogen,alkyl, aryl or aralkyl group. The R group can be unsubstituted orsubstituted, but if it is substituted then it should not comprisesubstituents that substantially interfere with the crosslinking reactionas is known and can be easily established by the skilled person. Inparticular, acidic substituents, for example carboxylic acids, arepreferably present only in insubstantial amounts and are most preferablynot included. This similarly applies to substituents on thecrosslinkable component and to cation X.

The catalyst C is a latent base catalyst because on drying, thecarbonate salt decomposes releasing carbon-dioxide to produce a strongbase; either a hydroxide or an alkoxy, or aralkyloxy base. In a pot, inparticular in a closed pot, the decomposition takes place only slowly,because the CO2 cannot escape to shift the reaction equilibria tocompletion, resulting in a good (long) pot life, whereas during dryingof the crosslinkable composition when applied as a coating layer, thebase is regenerated quickly resulting in good curing rate upon escape ofthe CO2 from the high surface area created. It was found that thecrosslinkable composition has even at very high solids content a longworkable potlife and a desirably fast drying and hardness build-upbehaviour under most if not all curing conditions. Higher amounts ofcatalysts can be used without significantly affecting the potlife and sothe crosslinkable composition can be used in pot-applications of thecoating by brushing or rolling or spraying. An extra advantage is theabsence of any yellowing even under high temperature stoving conditions.

We have surprisingly found that crosslinkable compositions comprisingsubstituted carbonate salts as latent crosslinking catalysts give verygood results in providing good balance of long pot-life in such highsolids polymer coating compositions while at the same time having highcuring rates during drying. Good results were obtained in crosslinkablecompositions having a very high solid content, preferably at least 60,65 or even more than 70 or more than 75 wt % (dry weight aftercrosslinking relative to the total weight of the crosslinkingcomposition). It is noted that the solids content relates to thecrosslinking composition not including particulate fillers or pigmentsthat maybe added at a later stage for example when making a coatingcomposition.

Components A and B are molecules and the functional groups are theacidic protons C—H and unsaturated C═C groups in said molecules. Thereactive functionality of a component is defined as the average numberof functional groups per molecule of that component. In a system inwhich component A and B are separate molecules, at least one ofcomponents A or B comprises on average more than 2 reactive functionalgroups to achieve a crosslinked network. This does not apply ifcomponent A and B are combined in one molecule.

The one or more reactive components A and B and catalyst C are mostconveniently present in the crosslinkable composition as separatemolecules. Preferably, reactive components A and/or B are separate andeach independently in the form of polymers, oligomers, dimers ormonomers comprising at least 2 reactive groups. For example, Component Acan be a malonate means that component A comprises one or more malonategroups, for example in a polymer. For coating applications, at least oneof component A or B preferably are oligomers or polymers.

The reactive components A and B can also be combined in one A-B typemolecule. In this embodiment of the crosslinkable composition both C—Hand C═C reactive groups are present in one A-B molecule. It is envisagedthat also Catalyst C can be combined in one molecule with component Aand/or B, preferably as a combination of AC or BC. However, catalyst Cmost preferably is a separate component as it is preferred to mix thecatalyst just before use to a composition comprising component A and B.

Component A: Activated Methylene or Methine (CH) Group-ContainingComponents

Components A comprising an activated C—H group have a structureaccording to formula 2:

wherein R is hydrogen or an alkyl or aryl and Y and Y′ are identical ordifferent substituent groups, preferably alkyl, aralkyl or aryl (R*), oralkoxy (—OR*) or wherein in formula 2 the —C(═O)—Y and/or —C(═O)—Y′ isreplaced by CN or aryl, preferably no more than one phenyl. Y or Y′ canbe amide, but preferably not both. According to the claimed inventioncomponent A is a malonate (Y and Y′ are —OR*), preferably a malonatecontaining polymer, preferably a polyester, polyurethane, acrylic orpolycarbonate. Also mixtures or hybrids of these polymer types arepossible.

Component A is a malonate containing compound means that preferably inthe crosslinkable composition the majority of the activated C—H groupsare from malonate, that is more than 50%, preferably more than 60%, morepreferably more than 70%, most preferably more than 80% of all activatedC—H groups in the crosslinkable composition are from malonate. Inanother embodiment, the crosslinking composition comprises a componentA, for example a polymer, wherein more than 50%, preferably more than70%, more preferably more than 80% and most preferably more than 90% ofthe activated C—H groups are from malonate and a separate component, forexample another polymer, oligomer or monomer, comprising activated C—Hgroups not from malonate.

The advantages of the invention are particularly manifest in criticallydifficult compositions comprising not only a high solids content butalso aimed at a high crosslinking density, with relative highconcentrations and functionalities of functional groups, for example incase the component A is a compound, in particular an oligomer orpolymer, comprising an average of 2 to 30, preferably 4 to 20 and morepreferably 4-10 activate C—H per polymer chain. The substituent R or R*groups can be unsubstituted or substituted, but as described above if itis substituted than evidently it should not comprise substituents thatsubstantially interfere with the crosslinking reaction.

Examples of suitable components containing activated methylene ormethine groups are generally disclosed in U.S. Pat. No. 4,871,822 (seeespecially column 4, lines 15-28), which components contain a methyleneand/or monosubstituted methylene group in the alpha-position to twoactivating groups such as, for example, carbonyl, cyano, sulfoxideand/or nitro groups. Preferred are components containing a methylenegroup in the alpha-position to two carbonyl groups, such as malonateand/or acetoacetate group-containing components, malonates being mostpreferred.

Suitable examples of malonate group-containing components may bementioned malonic acid esters as disclosed in U.S. Pat. No. 2,759,913(column 8, lines 51-52), and malonate group-containing oligomeric andpolymeric components as disclosed in U.S. Pat. No. 4,602,061 (column 1,line 10 through column 2, line 13). Preferred are the oligomeric and/orpolymeric malonate group-containing components such as, for example,polyesters, polyurethanes, polyacrylates, epoxy resins, polyamides andpolyvinyl resins containing malonate groups in the main chain, pendantor both.

The malonate group-containing polyesters can be obtained preferably bythe transesterification of a methyl or ethyl diester of malonic acid,with multifunctional alcohols that can be of a polymeric or oligomericnature. Malonate group-containing polyurethanes can be obtained, byreacting a polyisocyanate with a hydroxyl group-containing ester of apolyol and malonic acid, or e.g. by transesterification of an hydroxyfunctional polyurethane with a dialkylmalonate. Malonategroup-containing epoxy esters can be obtained by esterifying an epoxyresin with malonic acid or a malonic monoester, or acid functionalmalonate polyester, or by transesterification with a dialkyl malonate,optionally with other carboxylic acids and derivatives thereof. Malonategroup-containing polyamides, or polyamide-esters, can be obtained in thesame manner as the polyesters, wherein at least a part of the hydroxycomponent is replaced with a mono- and/or polyfunctional primary and/orsecondary amine. The malonate group-containing polyamides withmalonamide functionality are less preferred. Other malonategroup-containing polymers may be obtained by the transesterification ofan excess of a dialkyl malonate with hydroxy-functional acrylic polymer.In this manner, a polymer with malonate group-containing side-chains maybe formed. Any excess dialkyl malonate may be removed under reducedpressure or, optionally, be used as a reactive solvent.

Especially preferred malonate group-containing components for use withthe present invention are the malonate group-containing oligomeric orpolymeric esters, ethers, urethanes and epoxy esters containing 1-50,more preferably 2-10, malonate groups per molecule. In practicepolyesters and polyurethanes are preferred. It is also preferred thatsuch malonate group-containing components have a number averagemolecular weight (Mn) in the range of from about 100 to about 5000, morepreferably, 250-2500, and an acid number of about 2 or less. Alsomonomalonates can be used as they have 2 reactive C—H per molecule.Monomeric malonates can, in addition, be used as reactive diluents.

Suitable acetoacetate group-containing components are acetoacetic estersas disclosed in U.S. Pat. No. 2,759,913 (column 8, lines 53-54),diacetoacetate components as disclosed in U.S. Pat. No. 4,217,396(column 2, line 65 through column 3, line 27), and acetoacetategroup-containing oligomeric and polymeric components as disclosed inU.S. Pat. No. 4,408,018 (column 1, line 51 through column 2, line 6).Preferred are the oligomeric and/or polymeric acetoacetategroup-containing components.

Suitable acetoacetate group-containing oligomeric and polymericcomponents can be obtained, for example, from polyalcohols and/orhydroxy-functional polyether, polyester, polyacrylate, vinyl and epoxyoligomers and polymers by reaction with diketene or transesterificationwith an alkyl acetoacetate. Such components may also be obtained bycopolymerization of an acetoacetate functional (meth)acrylic monomerwith other vinyl- and/or acrylic-functional monomers.

Especially preferred of the acetoacetate group-containing components foruse with the present invention are the acetoacetate group-containingoligomers and polymers containing at least 1, preferably 2-10,acetoacetate groups. It is also especially preferred that suchacetoacetate group-containing components should have an Mn in the rangeof from about 100 to about 5000, and an acid number of about 2 or less.

Components containing both malonate and acetoacetate groups in the samemolecule are also suitable. Additionally, physical mixtures of malonateand acetoacetate group-containing components are suitable.Alkylacetoacetates can, in addition, be used as reactive diluents.

Again as exemplified by the previously incorporated references, theseand other malonate and/or acetoacetate group-containing components thatcan be used in the composition, and their methods of production, aregenerally known to those skilled in the art, and need no furtherexplanation here.

Component B: Activated Unsaturated Group-Containing Components

Suitable components B generally can be ethylenically unsaturatedcomponents in which the carbon-carbon double bond is activated by anelectron-withdrawing group, e.g. a carbonyl group in the alpha-position.Representative examples of such components are disclosed in U.S. Pat.No. 2,759,913 (column 6, line 35 through column 7, line 45),DE-PS-835809 (column 3, lines 16-41), U.S. Pat. No. 4,871,822 (column 2,line 14 through column 4, line 14), U.S. Pat. No. 4,602,061 (column 3,line 14 through column 4, line 14), U.S. Pat. No. 4,408,018 (column 2,lines 19-68) and U.S. Pat. No. 4,217,396 (column 1, line 60 throughcolumn 2, line 64). Acrylates, fumarates and maleates are preferred.Most preferably, the component B is an unsaturated acryloyl functionalcomponent,

A first preferred group of suitable components B are the acrylic estersof components containing 2-6 hydroxyl groups and 1-20 carbon atoms.These esters may optionally contain hydroxyl groups. Especiallypreferred examples include hexanediol diacrylate, trimethylol propanetriacrylate, pentaerythritol triacrylate, di-trimethylolpropanetetraacrylate. Apart from acryloyl esters a class of suitable componentsB are acrylamides.

As a second preferred example may be mentioned polyesters based uponmaleic, fumaric and/or itaconic acid (and maleic and itaconicanhydride), and di- or polyvalent hydroxyl components, optionallyincluding a monovalent hydroxyl and/or carboxyl component.

As a third preferred example may be mentioned resins as polyesters,polyurethanes, polyethers and/or alkyd resins containing pendantactivated unsaturated groups. These include, for example, urethaneacrylates obtained by reaction of a polyisocyanate with an hydroxylgroup-containing acrylic ester, e.g., an hydroxyalkyl ester of acrylicacid or a component prepared by esterification of a polyhydroxylcomponent with less than a stoichiometric amount of acrylic acid;polyether acrylates obtained by esterification of an hydroxylgroup-containing polyether with acrylic acid; polyfunctional acrylatesobtained by reaction of an hydroxyalkyl acrylate with a polycarboxylicacid and/or a polyamino resin; polyacrylates obtained by reaction ofacrylic acid with an epoxy resin; and polyalkylmaleates obtained byreaction of a monoalkylmaleate ester with an epoxy resin and/or anhydroxy functional oligomer or polymer.

Most preferred activated unsaturated group-containing components B arethe unsaturated acryloyl functional components. It is also especiallypreferred that the acid value of the activated unsaturatedgroup-containing components is sufficiently low to not substantiallyimpair activity of the catalyst, so preferably less than about 2, mostpreferably less than 1 mg KOH/g. As exemplified by the previouslyincorporated references, these and other activated unsaturatedgroup-containing components, and their methods of production, aregenerally known to those skilled in the art, and need no furtherexplanation here. Preferably the functionality is 2-20, the equivalentweight (EQW: average molecular weight per reactive functional group) is100-2000, and the number average molecular weight preferably is Mn200-5000.

Component C: The Latent Base Catalyst

The latent base catalyst generally is a substituted carbonate saltaccording to formula 1

wherein X⁺ represents a cation and wherein R is hydrogen, alkyl oraralkyl group. The cation must be non-acidic such that it does notinterfere with the base catalyst and can for example be alkali- orearth-alkali metal, in particular lithium, sodium or potassium, butpreferably is a quaternary ammonium or phosphonium ion according toformula 3,

wherein Y represents N or P, and wherein each R′ can be a same ordifferent alkyl, aryl or aralkyl group, R can be hydrogen, alkyl, arylor aralkyl group, wherein R and R′ can be bridged to form a ringstructure or R and/or R′ can be a polymer. As described above, R and R′can be substituted with substituents that do not or not substantiallyinterfere with the RMA crosslinking chemistry as is known to the skilledperson. Preferably, R is an alkyl or aralkyl group most preferably R isan alkyl having 1 to 4 carbon atoms. These simple alkyl carbonates canbe prepared easily by reaction of corresponding hydroxides withdialkylcarbonates or by the reaction of tertiary amines withdialkylcarbonates in alcohols.

The carbonate group and the cation can be linked in one molecule, forexample the latent crosslinking catalyst is a substituted carbonate saltaccording to formula 4

In another embodiment, the group R in the latent crosslinking catalystis a polymer and/or X is a quaternary ammonium or phosphonium whereinone R′ group is a polymer. Such a catalyst is obtainable by quaternisinga polymer, preferably a polyacrylate, comprising a pending tertiaryamine, preferably 2-(dimethylamino)ethylmethacrylate, with adialkylcarbonate to form a quaternary ammonium carbonate according toformula 1, 3 or 4.

Quaternary ammonium compound components, such asdidecyl-dimethylammoniumcarbonate and didecyl-dimethyl ammoniumchloride,are well known and used for its antimicrobial activity and woodpreservation. The preparation of the quaternary ammonium carbonates iswell known in the art. U.S. Pat. Nos. 6,989,459 and 452,635,100,describe a process for an in situ method of preparing quaternaryammonium methylcarbonate salts and quaternary ammonium alkylcarbonatesalts in high yield from tertiary amines, methanol, and at least one ofa cyclic carbonate, an aliphatic polyester, and an ester, and theirsubsequent conversion to quaternary ammonium bicarbonates, quaternaryammonium carbonates or both in a one-pot reaction.

Quaternisation of trialkylamine with dialkylcarbonate or cycliccarbonate leads at a high temperature under autogeneous conditions tocomponents of formula 1. Polymers containing tertiary amine groups canalso be quaternized with e.g. dimethylcarbonate to a quaternizedpolymeric ammonium methylcarbonate salt. Using2-(dimethylamino)ethylmethacrylate (MADAM) as sole monomer or ascomonomer in polyacrylates offers a means to get polymers containingtertiary amines suitable for quaternisation with dimethylcarbonate. Manyothers are possible such as epoxy containing resins modified withsecondary amines or isocyanate containing products treated with e.g.2-dimethylaminoethanol. The described prior art processes and a novelprocess are herewith incorporated by reference.

A preferred way to synthesize the catalyst is by reaction of thequaternary ammonium hydroxide with dialkylcarbonate to form a catalystaccording to formula 1 or 3 or cyclic carbonate according to formula 4.This is done at room temperature by mixing some molar excess of liquidcarbonate with a solution of the ammonium base. The blocking (conversionof hydroxide to alkylcarbonate) can be shown by means of titration withaqueous HCl titration: for the blocked catalyst an equivalence point ata lower pH is found. The scheme below illustrates for one embodiment ofthe invention the synthesis of a blocked catalyst and its decompositionto an alkoxide base. When applied in an RMA binder composition, thealkoxide abstracts a proton from the activated methylene or methinewhich, as a nucleophilic anion, subsequently adds on the double bond ofthe activated unsaturated group and abstracts a proton from anotheracidic methylene to initiate the next reaction.

It has been found that the potlife (defined as the time required to adoubling of the viscosity) or the gel-time (i.e. time to get a non-fluidformulation) is longer when the quaternary ammonium alkylcarbonates offormula 1 have two, preferably three of the four R radicalsindependently each more than 4 carbons but at most 18 carbons and theremaining R at least 2 carbons Good results can generally be obtained ifthe R groups on the quaternary cation comprise 4-18 carbon atoms.Surprisingly good results were also obtained with longer alkyl groupswherein the cation comprises at least two, preferably three or, morepreferably, all four R′ groups between 5 and 18 carbon atoms and theremaining R′ groups comprise 1-18 carbon atoms. Tetrahexylammoniummethylcarbonate, tetradecyl-(i.e.C-14)-trihexy-lammonium-methylcarbonate and tetradecylammoniummethyl-carbonate for instance yielded longer potlifes thantetrabutylammonium methylcarbonate, benzyltrimethylammoniummethylcarbonate, or trihexylmethylammonium methylcarbonate ortrioctylmethylammonium methylcarbonate. These organic groups on thequaternary ammonium or phosphonium cation provide good compatibility ofthe catalyst with the polymer binder and organic solvents as well asgood potlife.

Good results were obtained with tetrahexylammonium bicarbonate. It wasfound that tetrahexylammonium bicarbonate shows a potlife/drying balancebeing comparable with tetrahexylammonium methylcarbonate but better thantetrabutylammonium methylcarbonate and much better thantetrabutylammonium bicarbonate. So, the bulky substituents on thenitrogen are more important in determining the potlife than the type ofcarbonate. Experimental work of the inventors has shown that very goodpotlife/drying behavior and resin compatibility was obtained withtetrabutylammonium methylcarbonate catalyzed RMA and certainly withalkyl ammonium methylcarbonate with more bulky alkyl groups. Goodpotlifes could also be obtained when at least 1 R radical in formula 1is a polymer such as MADAM containing polyacrylates quaternised withdimethylcarbonate.

The Crosslinkable Composition:

The present invention relates in particular to a crosslinkablecomposition comprising the above-mentioned components A, B and C. Thecrosslinkable compositions in accordance with the present invention arein general suitable for a variety of applications, such as coatings,adhesives, inks, film forming material, composites, moulding materialetc. The most important application is in coating compositions, forexample, as paint, impregnating, sealing and bonding compositions,especially for protective coatings for metals, plastics, wood and otherwell-known substrates. These coating compositions possess extendedpotlife, very good curing rates, and a good balance of physical andmechanical properties making them especially well suited for theaforementioned uses.

In the crosslinkable position, it is preferred that the ratio of thenumber of activated acidic protons CH in component A to the number ofactivated unsaturated groups (C═C) in component B (the CH/C═C ratio) isin the range between 10 and 0.1, more preferably between 5 and 0.2, evenmore preferably between 2 and 0.5, most preferably between 1.5 and 0.8.As mentioned earlier, the described components A and B react with eachother through a Michael addition, in which the activated CH group ofcomponent B, when deprotonated, adds to one of the carbon atoms of theactivated unsaturated group of component A. Hereby, the activatedmethylene can in principle be equivalent with 2 activated methine (CH)groups. This is only the case for those A/B combinations wherein bothprotons are reactive; in case of a system comprising acryloyl/malonatereactive groups 2 protons of the malonate group can react. For curingwith maleates, this is not the case; the second C—H is no longerreactive once one maleate has been added.

Further, it is preferred that the latent crosslinking catalyst isutilized in an amount ranging between 0.001 and 0.3 meq/g solids,preferably between 0.01 and 0.2 meq/g solids, more preferably between0.02 and 0.1 meq/g solids (meq/g solids defined as mmoles latent baserelative to the total dry weight of the crosslinkable composition, notcounting particulate fillers or pigments).

It was surprisingly found that significantly better potlife could beachieved in a composition wherein component A is a malonate (Y and Y′are —OR in formula 2) and which composition further comprises 0.1-10 wt%, preferably 0.1-5, more preferably 0.2-3, most preferably 0.5-1.5 wt %and most preferably 0.5-2 wt % water (relative to total weight of thecoating composition). Preferably, the amount of water is chosen in aneffective amount to increase gel time with at least 15 minutes,preferably at least 30 min, more preferably at least 1 h, even morepreferably at least 5 h, and most preferably at least 24 h, 48 h. or atleast 10%, 50% or 100% compared to the same composition without water.It is highly surprising that such improvement can be obtained by suchsmall amounts of water.

Preferably, the composition further comprises an alcohol R″—OH whereinR″ is a substituted or unsubstitued alkyl, (or aralkyl) which is same ordifferent from the R of the carbonate. Preferably, the catalyst is addedin such alcohol solvent to the other components of the crosslinkablecomposition, or the alcohol is present or added to the crosslinkingcomponents.

An improvement of the shelf life of the catalyst solution used can beobtained if the catalyst further comprises a compound RO—C(═O)O—Rwherein R is preferably the same as R of the catalyst in formula 1, 3 or4, where preferably the molar ratio of II to the mole of carbonate inthe catalyst is 0.01-50, wherein water and component II are present inan amount of more than 1 mole % with respect to the catalyst. It isbelieved that the presence of the compound RO—C(═O)O—R in thecrosslinkable composition allows regeneration of the blocked catalystwhen premature CO₂ loss occurs.

It was found that the open time can be improved when a crosslinkablecomposition comprising components A and B as described above comprises,in addition to malonate component A, a second component A2 alsocomprising reactive acidic protons but having a higher acidity thancomponent A and which preferably also is reactive towards component B.It was found that this generally applies to crosslinkable compositionsirrespective of the nature of the latent base catalyst used. In afurther improved embodiment the crosslinkable composition of the presentinvention also comprises in addition to malonate component A, a secondcomponent A2 also comprising reactive acidic protons but having a higheracidity than component A and which also is reactive towards component B.

Preferably, the crosslinkable composition comprises, in addition tomalonate component A, a second C—H acidic component A2 with a higheracidity than that on component A that is also reactive towards componentB with an RMA reaction. The component A2 can optionally also be bondedto component A in one molecule. It was surprisingly found that suchcrosslinkable compositions result in coatings having a faster hardnessbuild-up, less solvent inclusion and improved appearance, in particularless skin formation and wrinkling during curing. This can also extendthe pot life in some formulations. The aforementioned advantages of thepresence of a second more acidic C—H acidic component A2 can also beobtained in RMA systems with catalyst systems other than the latent basecatalysts according to the invention, for example in combination withthe latent base catalyst described in the prior art described above, inparticular also by Noomen. All these benefits are obtained whilesacrificing only a limited time in surface drying, that is extremelyfast anyway in particular for the RMA compositions of this invention.

Without wishing to be bound by theory, it is believed that the protonabstraction from the acidic methylene or methine groups on RMA componentA does not take place substantially until the protons from the secondRMA component A2 are used up, which goes very slow in the pot andquicker upon activation of the catalyst in the drying and curing film.The reactivity of anions of the component A2 is believed to be less thanthat of anions of component A. Once C—H's of the moderator components A2have reacted with component B, the main component A will be deprotonatedand start reaction with component B and crosslinking and hardeningstarts and proceeds quickly, substantially uninfluenced by the initialpresence of component A2, just postponed by a tunable inhibition time.All base from the catalyst becomes available again on complete dryingfor deprotonating the component A.

Preferably, in this embodiment A is malonate and A2 is a componentaccording to formula 2 having higher acidity by choice of a different Rand/or of a different Y and/or Y′. The difference in acidity of the twoC—H acidic components A and A2 is chosen preferably in that wherein thepKa of component A2 is between 0.5 and 6, preferably between 1 and 5 andmore preferably between 1.5 and 4 units lower than the pKa of componentA. Preferably, component A is a malonate containing component andcomponent A2 is an acetoacetate or acetylacetone containing component.

Generally good results can be obtained when the amount of activatedmethine or methylene functional groups having the lower pKa (A2) isbetween 0.1 and 50 mole %, preferably between 0.2 and 40 mole %,preferably between 1 and 30 mole %, preferably between 1 and 40 mole %,more preferably between 2 and 30 mole %, and most preferably between 2and 20 mole % (of the total mole of activated methine or methylenefunctional groups) and in particular when the C—H functionality ofcomponent A2 is lower than the C—H functionality of A, preferably theC—H functionality of A2 is 1-10, 1-6, 1-4, 2-6, 2-4 or 2-3 wherein thefunctionality is average number of active C—H per molecule.

Most preferably, the components A and A2 are present as a mixture ofpolymeric component (A1) comprising malonate groups and a polymericcomponent (A2) comprising acetoacetate and/or acetylacetone groups. Thisimprovement is particularly useful in compositions for high hardnesscoatings (high Tg, crosslink density).

Depending on the choice of the crosslinkable components, in particularcomponents A and B in the RMA system, the crosslinkable composition canhave a certain amount of an organic solvent or can have no solvent atall. However, the inventors found that particular and unexpectedadvantage in open time and hardness development can be achieved if inthe crosslinkable composition at least part of the solvent is an alcoholsolvent. The solvent can be a mixture of a non-alcoholic solvent and analcohol solvent. Preferably, the alcohol is present in an amount of atleast 1, preferably 2, more preferably 3, most preferably at least 5,even more preferably at least 10 wt % relative to the total weight ofthe crosslinkable composition and in view of VOC constraints preferablyat most 45, preferably at most 40 wt %.

The alcohol solvent preferably is one or more primary alcohols, morepreferably a mono-alcohol having 1 to 20, preferably 1-10, morepreferably 1-6 carbon atoms, preferably selected from the group ofethanol, n-propanol, n-butanol, n-amyl alcohol and butylglycol. Forthese preferred compositions it was surprisingly found that due to thepresence of the alcohol solvent the viscosity of the composition in aclosed container remains very low even after extended periods of time,while maintaining fast drying characteristics The absolute value of theviscosity depends on the application viscosity chosen. It is howeverimportant that the viscosity does not increase rapidly. Preferably theviscosity of the composition after addition of the catalyst does notincrease more than a factor 2 within 4 hours, preferably 6 hours, morepreferably 8 hours and most preferably 12 hours in a closed container atroom temperature. Methanol is less preferred because of the health,environmental and safety risks.

The many advantages of the invention of a longer potlife and improvedopen time in the various embodiments as described above can also beobtained in coating compositions having solid contents lower than 55 wt%. In particular the invention also relates to a crosslinkablecomposition comprising reactive components A and B each comprising atleast 2 reactive groups wherein the at least 2 reactive groups ofcomponent A are acidic protons (C—H) in activated methylene or methinegroups and the at least 2 reactive groups of component B are activatedunsaturated groups (C═C) to achieve crosslinking by Real MichaelAddition (RMA) wherein the component A is a malonate containingcomponent and wherein components A and B react upon deblocking of latentbase catalyst C by evaporation of carbon dioxide, which latent basecrosslinking catalyst is a substituted carbonate salt according toformula 1.

In summary, the most preferred embodiment is a crosslinkable compositioncomprising

a) a malonate containing compound as component A,

b) an unsaturated acryloyl functional compound as component B,

c) optionally component A2 comprising acetoacetate or acetylacetonegroups having 0.1-50 mole % activated C—H on total activated C—H inmethine or methylene functional groups in components A and A2), whereinthe ratio of the number of activated acidic protons in component A+A2 tothe number of activated unsaturated groups on component B is in therange between 0.5 and 2.0,d) which crosslinkable composition preferably has a solids content ofpreferably at least 55 wt %, 65%, 70% or even at least 75% (dry weightafter crosslinking relative to the total weight of the crosslinkingcomposition),e) 0.001-0.3 meq/g solids (mole carbonate relative to the total dryweight of the crosslinkable composition) of latent base crosslinkingcatalyst C being a substituted carbonate salt according to formula 1

wherein X represents a non-acidic cation and wherein R is hydrogen, analkyl, or aralkyl group,f) optionally 0.1-5 wt % water (relative to total weight of the coatingcomposition),g) optionally an alcohol comprising solvent.The Coating Composition:

The invention further relates to a coating composition comprising thecrosslinkable composition according to the invention as a binder andoptional usual coating additives. The coating composition preferably hasa solids content of between 55 and 100%, and 0 to 45 wt % solvent and adry to touch time at room temperature between 5 to 120 min, preferably 5to 60 min. and a gel time of at least 3 hours, preferably at least 6hours, most preferable at least 9 hours at room temperature. The coatingcomposition has low VOC and excellent properties, in particular goodpotlife/drying balance as described above. Such coating compositionspreferably are free of inhibition, are free-to-handle within 8 hrs andexhibit a sufficient degree of curing within 7 days, detailed demandsdepending on the exact application.

Depending upon the field of application, the coating compositions inaccordance with the present invention may optionally contain one or morepigments, dyes and usual intermediary agents, additives and/or solvents.Examples of suitable inert organic solvents include esters, ketones,ethers, alcohols, aromatic and aliphatic hydrocarbons. Examples ofsuitable reactive organic solvents include dimethyl malonate, diethylmalonate, ethyl acetoacetate and 2-ethylhexyl acrylate (mono-acrylatesshould be counted as compound B in terms of total functionality andbecause they are chain stoppers should not be present in too highamounts).

As examples of preferred additives may be mentioned minor amounts of aco-binder not containing activated unsaturated or CH acidic groups, forexample, cellulose acetate butyrate, acrylic, epoxy and polyesterresins. As is known to one skilled in the art, these co-binders arecommonly utilized in the coatings industry to modify certain propertiessuch as drying speed and adhesion to substrates.

As mentioned earlier, the coating compositions in accordance with thepresent invention are suitable for a variety of coatings uses, forexample, as paint, impregnating, sealing and bonding compositions. Apreferred application is as a primer, topcoat, or clearcoat; the coatingcompositions may be applied to a substrate in any convenient manner suchas, for example, by brushing, spraying or dipping. Suitable substratesinclude metals, wood, board, plastics and leather.

The curing of the above-described coating composition is preferablycarried out at elevated temperatures above about 0° C. generally betweenabout 5° C. and about 150° C. Preferred coating compositions based onRMA crosslinkable composition comprising components A, B and C asdescribed are preferably cured at curing temperature is between 0 and80° C., preferably 5 to 60° C., most preferably between 5 and 30° C.

The invention further relates to a catalyst composition for use as alatent base crosslinking catalyst in a crosslinkable composition,preferably according to the above described invention comprising

-   -   a. a substituted carbonate salt catalyst according to formula 1

wherein X⁺ represents a non-acidic cation and wherein R is hydrogen,alkyl, aryl or aralkyl group, in an amount of at least 0.01, preferablyat least 0.2, more preferably at least 0.4 meq/gr cat composition,further comprising one or more of the features b) to e);

-   -   b. wherein the catalyst is a substituted carbonate salt        according to formula 4,    -   c. wherein R in formula 1 or 3 is an alkyl, aryl or aralkyl        group,    -   d. further comprising an additional compound II with the formula        RO—C(═O)O—R wherein R is alkyl, aryl or aralkyl group and        wherein the molar ratio of compound II to the mole of        substituted carbonate salt in the latent base catalyst is        0.01-50,    -   e. further comprising water in amount between 0.1-80 wt %,        preferably 1-50 wt % relative to total weight of the catalyst        composition,    -   f. optionally further comprising an organic solvent at least        part of which is an alcohol.    -   g. optionally further comprising an excess carbondioxide        dissolved in the catalyst composition.

Organic solvent, in particular alcohol containing solvent can be addedto the catalyst but is optional as it is for another purpose to improvehardening and viscosity build up of the crosslinking composition and ispreferably added later to the crosslinkable composition if needed. Thealcohol is not needed for the catalyst function and in a particularembodiment the catalyst does not contain alcohol. Similarly the excesscarbondioxide is optional.

The invention in particular relates to a catalyst composition for use asa latent base crosslinking catalyst comprising a substituted carbonatesalt X⁺⁻O—C(═O)O—R according to formula 1, 3 or 4, in which theconcentration of latent base is 0.03-3 meq/gram based on total weight,preferably further comprising 0.5-70 wt % water (relative to totalweight of the catalyst composition). As described above these novelcatalyst compositions show very useful properties as acid base catalystin crosslinking compositions.

In a preferred embodiment, the catalyst composition further comprises acompound RO—C(═O)O—R wherein R is the same as R in formula 1, 3 or 4 butnot hydrogen, wherein preferably the molar ratio of the amount of waterto compound RO—C(═O)O—R (II) is near 1, the molar ratio of II to themole of carbonate in the catalyst is 0.01-50 As described above, thecatalyst composition has an improvement shelf life.

The invention also relates to the use of a substituted carbonate salt ofthe formula X⁺⁻O—C(═O)O—R according to formula 1, 3 or 4 as a latentbase crosslinking catalyst, preferably in RMA crosslinkablecompositions, in particular to the use in a low temperature curingcoating composition wherein curing temperature is between 0 and 80° C.,preferably 5 to 60° C., most preferably between 5 and 30° C.

The invention further relates to the use of excess carbon dioxidesolubilized in the paint formulation, e.g. supplied as dry ice (solidcarbondioxide) to extend the pot-life of the crosslinkable compositioncomprising adding dry ice to the crosslinkable composition or to thecoating composition or the catalyst composition according to theinvention. Pressuring the paint with gaseous CO₂ would be anotherapproach to this concept.

The foregoing more general discussion of the present invention will befurther illustrated by the following specific examples, which areexemplary only.

The gel time is the time at which the sample is gelled and has lost allfluidity which was determined by making a mixture of the components andthe latent base catalyst, placing 10 ml sample of the mixture in a 20 mlclosed glass container (50% headspace) and keeping the sample at roomtemperature until gelation occurs. The container was tilted at regulartime intervals and visually inspected to check whether or not the samplestill flowed. The gel time is the time at which the container could beheld upside down without flow of the sample.

Dust-dry and touch-dry times were measured according to the so-calledTNO method with a wad of cotton-wool. Dust-dry time means the timeneeded for the coating after dropping the wad on the surface of thecoating and after leaving it there for 10 second, to get no residue ofthe wool-cotton sticking onto the surface after blowing away the wad.For touch-dry time the same holds but now a weight load of 1 kg isapplied on the wad for 10 seconds.

For measuring solvent resistance, spot tests were carried out bycontacting the film with a small wad of cotton wool that had beencompletely soaked in solvent for 5 minutes. After the removal of thecotton wool, the spot was swept dry with a tissue and the damage to thefilm was visually observed and rated as 1 to 5. In this score 1 standsfor completely intact and 5 for severely affected.

Persoz pendulum hardness was measured in a climatized room at 23° C.,and 55+/−5% relative humidity. Reported molecular weights were measuredby GPC, and expressed in polystyrene equivalent weights. Viscositieswere measured with a TA Instruments AR2000 Rheometer, using a cone andplate setup (cone 4 cm 1°) at 1 Pa stress. Viscosity development inclosed containers was measured using Gardner-Holt bubble tubes, andtranslating the times found to viscosity units using known relations.

A: Syntheses of Activated Methylene Resins

A-1. Preparation of Malonate Polyester A-1

Into a reactor provided with a distilling column filled with Raschigrings were brought 192.4 g of 2-butyl, 2-ethyl-propanediol-1,3, 125 g ofneopentylglycol, 269.3 g of dimethylmalonate; 0.58 g ofdibutyltindioxide and 10 g of o-xylene. The mixture was heated to 140°C. with stirring under a nitrogen atmosphere. In two hours, about halfof the expected methanol was distilled off, then 43 g of o-xylene wasadded and the temperature was progressively increased to 200° C. in 4hours. After distilling off the rest of the expected methanol, most ofo-xylene was removed from the mass, with the help of vacuum. The nearlycolorless material was cooled down and diluted with o-xylene to a 90%solid content. The solution had a viscosity of 3.4 Pa·s as determinedwith a cone-and-plate rheometer, an OH value of 83.2 mg KOH/g, an Mn of1900 and methylene equivalent weight of 224/g solid material (calculatedfrom the theoretical input of the synthesis).

A-2. Preparation of Malonate Polyester A-2

Following the procedure of B-1, 86.50 g of 1,4-cyclohexanedimethanol,96.20 g of 2-butyl, 2-ethyl-propanediol-1,3, 125 g of neopentylglycol,326.72 g of diethylmalonate, 0.58 g of dibutyltindioxide and 10 g ofo-xylene were fed into a reactor and reacted. The resulting nearlycolorless material was cooled down and diluted with o-xylene to a 89.3%solid content. This solution had a viscosity of 9.0 Pa·s, an OH value of84.2 mg KOH/g, an Mn of 1700 and a methylene equivalent weight of 219/gsolid material.

A-3. Preparation of Acetoacetate Acrylic Resin A-3

A three-necked flask was charged with 17.7 grams α-methylstyrene dimer(AMSD, 0.075 mol) and 18.1 grams o-xylene. The flask is provided with adropping funnel and a reflux cooler. The flask is placed in a heatingbath with oil at 153° C. and the content of the flask is heated undernitrogen to the reflux temperature of xylene. The monomer/peroxidemixture, 132.5 grams acetoacetoxyethylmethacrylate (AAEM, 0.618 mol))and 4.5 grams Trigonox 42S, is added dropwise from the dropping funnelto the flask in about 6 hours. During the reaction the reflux of xyleneis decreasing which is compensated by an increase of the oil temperatureto 170° C. After adding the given amount monomer-peroxide the flask waskept at the reaction temperature for another hour to complete thereaction. The resulting resin had an Mn of 1770, Mw 2825, and solidcontent SC of 83%.

A-4. Preparation of Acetoacetate Acrylic Resin A-4

In a similar procedure as described for A-3, another acetoacetatefunctional acrylic resin was prepared, now using 7.8 g AMSD, 11.9 gramso-xylene, 132.9 g AAEM, 10.7 g of HEMA and 4.6 g Trigonox 42S were used.Dowanol was used to dilute to SC of 74%. The resulting acrylic had an Mnof 3550 and Mw of 5540.

A-5: Preparation of Malonate Acrylic Resin A-5

An acrylic polyol intermediate was used (prepared from a mixture of 812g styrene, 585 g methyl methacrylate, 1267 g butyl acrylate, 585 ghydroxypropyl acrylate, 21 g Cardura E-10P), polymerized to a MMD withMn 2188, Mw 4844 and OH equivalent weight of 800. 1440 grams of thispolyol was charged to a 3 L flask and 720 g of diethyl malonate wasadded along with a packed column and an unprimed Dean-Stark Trap. Thereaction mixture was heated slowly to 200° C. by which time 75 g ofethanol had distilled off. Vacuum was attached to remove 432 g excessdiethyl malonate. The malonated acrylic polymer was then thinned with363 g of xylene, to a 80.1% SC, an Mn of 2901, and a Mw of 27200, and amalonate equivalent weight of 966.

A-6: Preparation of Malonate Polyester A-6

1980 g of dimethyl malonate and 268 g of trimethylolpropane were addedto a 5 L flask equipped with a packed column and an unprimed Dean-StarkTrap. The solution was heated to 183° C. over 4.5 hours over which time186 g of methanol had distilled out. Vacuum was attached and the excessdimethyl malonate was removed up to 183° C. Malonate equivalent weightis 145 g/mole.

A-7: Preparation of Malonate Polyester A-7

387 g of trimethylolpropane, 1780 g of neopentyl glycol, 1381 g ofisophthalic acid and 50 g xylene were charged to a 5 L flask equippedwith a packed column and a xylene-primed Dean-Stark trap and the mixtureheated to 240° C. After 9 hours of reaction had proceeded to an acidvalue of 3.1 by which time 312 g of water had been distilled off. 1650 gof dimethyl malonate were then added and the reaction mixture slowlyreheated to 223° C. over 7 hours, by which time 518 g of methanol haddistilled through the packed column. Methyl Amyl Ketone (721 g) was thenadded to yield an 85% sc resin with Mn 1818, Mw 4598, and a malonateequivalent weight of 360 g/mole.

B: Acryloyl Containing Compounds

B-1: Trimethylolpropanetriacrylate (TMPTA) B1

was obtained from Aldrich, MW=296; 100 mPa·s at 25° C.; 10.1 meq C═C pergram.

B-2: Di-(Trimethylolpropane)Tetraacrylate (Di-TMPTA) B2

was obtained from Aldrich, MW=466; 1250 mPa·s at 25° C.; 8.6 meq C═C pergram

B-3: An Acryloyl Urethane B-3

was prepared as follows. 243 grams of Vestanat T 1890 (IPDI trimer) wasmixed with 160 grams of dry butylacetate, and heated to 65° C. 185 mgDBTL was added. 117 g of hydroxypropylacrylate (treated before withaluminum oxide to reduce acid levels, and mixed with an additional 25 mgMEHQ inhibitor) was added slowly over 90 minutes, temperature notexceeding 67° C. When feeding was completed, reaction was continued for60 minutes at 65° C., and 3 hours at 75° C. NCO titration proves thatthe conversion is very high. Finally, 10 grams of methanol is added.

B-4: Acryoyl Urethane B-4

1512 grams of IPDI Isocyanurate Trimer IDT-70B (ex Rhodia, 70% inbutylacetate), 0.25 g butylated hydroxyl toluene and 0.38 gdibutyltindilaurate were added to a 3 L flask blanketed with nitrogenand heated to 80° C. 488 g of 2-hydroxyethyl acrylate were added over 1hour at 80-81° C. The reaction mixture was then held at 80° C. for 6hours during which time the NCO content was monitored by FTIR. It wasthinned down with 194 g of butyl acetate. The resulting product has a70.8% solids content.

C: Syntheses of Blocked Catalysts

C-1: Tetrahexylammonium Methylcarbonate

10 g of a 10% b.w. solution of tetrahexylammonium hydroxide (2.7 mmole)in methanol was mixed with 1 g (11 mmoles) of dimethylcarbonate (DMC) toyield a clear, colorless solution. Titration in 2-propanol with aqueousHCl after 24 hours revealed an equivalence point at a lower pH for theblocked versus the unblocked form and indicated complete blocking to0.26 meq methylcarbonate per g solution.

C-2: Tetradecyl, Trihexylammonium Methylcarbonate

With a similar procedure as for C-1, tetradecyl, -trihexylammoniumhydroxide (2.48 mmole) in methanol was mixed with 12.5 mmoles of DMC.This yielded a clear, colorless solution of 0.348 meq of methylcarbonateper g solution

C-3: Tetrakisdecylammonium Methylcarbonate

As above, tetrakisdecylammonium hydroxide (1.0 mmole) in methanol wasmixed with 6.7 mmoles DMC, to yield a clear solution of 0.15 meqmethylcarbonate per g solution.

C-4: Tetrabutylammonium Methylcarbonate

As above, 30 g of a 40% b.w. solution of tetrabutylammonium hydroxide(46.0 mmole base) in methanol was mixed with 45 g DMC. After decantationof some precipitate, a clear solution of 0.68 meq methylcarbonate per gsolution was obtained.

C-5 Tetrabutylammonium Ethylcarbonate

As described for C4, 46 mmole tetrabutylammonium hydroxide in methanolwas mixed with 45 g diethylcarbonate, to yield a solution of 0.64 meq/gethylcarbonate.

C-6 Tetrabutylammonium Propylenecarbonate

As described for C4, 31 mmole tetrabutylammonium hydroxide in methanolwas mixed with 30 g (292 mmoles) of propylenecarbonate, to obtain asolution of 0.63 meq/g hydroxypropylcarbonate.

C-7 Hexadecyltrimethylammonium Methylcarbonate

As described for C-4, 34 mmole hexadecyltrimethylammonium hydroxide inmethanol was mixed with 11 g DMC, to obtain a solution of 0.56 meq/gmethylcarbonate.

C-8 Benzyltrimethylammonium Ethylcarbonate

As described for C-4, 24 mmole benzyltrimethylammonium hydroxide (TritonB) in methanol was mixed with 15 g diethylcarbonate, to obtain a clearsolution of 0.93 meq/g ethylcarbonate.

C-9 Trihexyl, Methylammonium Methylcarbonate

In a pressure reactor, 75 g of trihexylamine (0.278 mole) was mixed with150 g DMC and 150 g methanol. This mixture was heated for 8 hrs at 100to 130° C. at an internal pressure up to 10 bar. After cooling, theyellowish solution was obtained of 0.475 meq/g of trihexyl,methylammonium methylcarbonate, and 0.322 meq/g of trihexylamine.

C-10 Trioctyl, Methylammonium Methylcarbonate

In a similar procedure as C-9, 100 g of trioctylamine (0.283 mole) wasmixed with 152 g DMC and 150 g of methanol. After cooling down, from theyellowish solution the trioctylamine was separated in a funnel as theupper layer, and to each part of the remaining solution was added 1 partof Dowanol PM i.e. propyleneglycol methylether yielding clear solutions.Titration showed 0.124 meq/g TOA and 0.213 meq/g of trioctyl,methylammonium methylcarbonate.

C-11: Synthesis of a Polymeric Catalyst; Random Copolymer ContainingMADAM

A reaction vessel for producing acrylic resin, which was equipped with astirrer, thermometer and a reflux condensing tube was charged with ahomogenous mixture of 61.35 g alpha-methyl-styrenedimer (AMSD), 29.63 gof butylmethacrylate (BuMA), 18.04 g of 2-hydroxypropylmethacrylate(HPMA), 9.91 g 2-ethylhexylmethacylate (EHMA) and 12.66 g of2-(dimethylamino)ethylmethacrylate (MADAM). The vessel was heated understirring and brought at 145° C. while nitrogen-substituting the insideatmosphere of the reaction vessel. Under maintaining the temperature at145° C. over a period of 5 hours, a mixture was dosed of 267.14 g ofbutylmethacrylate, 155.58 g 2-hydroxypropylmethacrylate, 89.13 g ofethylhexylmethacrylate, 113.94 g of 2-(dimethylamino)ethylmethacrylate(MADAM) and 11.62 g Perkadox AMBN (i.e.2,2-Azodi(2-methyl-butyronitrile). Thereafter in 30 minutes 1.17 gPerkadox AMBN dissolved in 31.90 g heptanone-2 is added. The materialwas cooled down and 369 g of dimethylcarbonate and 369 g of methanol wasadded in order to obtain a 48% solution of the at random polymer with anMn of 2400. It has an OH value of 78 mg KOH/g solid, and an amine valueof 1.05 meq/g solid. The solution was then heated in a high pressurereactor at 100° up to 110° C. and at pressure of 7 to 10 bar for about12 hours, to yield a solution containing 0.48 meq/g methylcarbonate and0.05 meq/g of remaining tertiary amine.

C12: Tetrabutylammonium Bicarbonate

A tetrabutylammoniumbicarbonate solution was made by diluting 20 gramsof a 40 wt % tetrabutylammonium hydroxide solution in methanol with 30grams of methanol, and treatment with carbondioxide gas until a contentof 0.66 meq blocked base per g solution was found by titration.

C13: Tetrahexylammonium Bicarbonate

A tetrahexylammonium bicarbonate solution was made by treatment of a 10wt %. tetrahexylammonium hydroxide solution in methanol withcarbondioxide gas until a content of 0.27 meq/g bicarbonate was found bytitration.

C14: Tetrabutylphosphonium Methylcarbonate

An aqueous solution of tetrabutylphosphonium hydroxide (40% in water)was diluted with methanol to a 10 wt % solution. To 10 g of thissolution (3.6 mmole base), 1 g DMC was added (22 mmole). After a day, itwas titrated, and contained 0.346 meg/g blocked base.

C15: Tetramethylammonium Methylcarbonate

A solution of 25 wt % tetramethylammonium hydroxide in methanol wasmixed with 10 grams of DMC. Initially turbid, the solution becomesclear, and exhibits a blocked base concentration of 1.37 meq/g.

C16: Benzyltrimethylammonium Bicarbonate

As described for C-13, a solution of benzyltrimethylammonium hydroxide(Triton B) in methanol was reacted with gaseous CO2, to obtain a clearsolution of 0.986 meq/g.

C17: Prepared from Aqueous Tetrabutylammonium Hydroxide andDimethylcarbonate

A flask is charged with:

35.8 grams of a 40% tetrabutylammonium hydroxide solution in water

21.7 grams dimethylcarbonate

1.5 grams isopropanol

This mixture is stirred gently for 20 hrs, and its active base contentwas determined by titration to be 0.7 meg/g.

C18: Prepared from 1M Methanolic Tetrabutylammonium Hydroxide andDimethylcarbonate

A flask is charged with:

76.68 g of 1M tetrabutyl ammonium hydroxide solution in methanol

77 g of dimethylcarbonate

5 g of methanol

Stirred for 20 hours, allowed to settle for a few days, filtered andthen analysed. Titration found the catalyst concentration to be 0.455meq/gram of solution.

Other Chemicals applied in the examples

-   -   TMG=tetramethylguanidine MW=115.18; b.p. 160° C.    -   DBU=1,8-diazabicyclo[5,4,0]undec-7-ene MW=152.24; b.p. 261° C.    -   DABCO=1,4-diazabicyclo[2.2.2.]octane MW=112.18    -   TBAH=40% solution of tetrabutylammonium hydroxide (MW=259.46) in        methanol, unless otherwise specified    -   THAH=10% solution of tetrahexylammonium hydroxide (MW=371.68) in        methanol    -   Setalux 8539 BA76 from Nuplex Resins bv. Epoxy containing        polyacrylate in butylacetate s.c.=76% 4.5 meq epoxy/g solids        Visco: 14 Pa·s at 23° C.    -   Acetylacetone    -   TMPTA: trimethylolpropanetriacrylate    -   TMPTAA: trimethylolpropanetriacetoacetate    -   Dowanol PMA: propylene glycol methyl ether acetate    -   MPK: methyl propyl ketone    -   MIBK: methyl isobutyl ketone    -   MAK: methyl amyl ketone    -   NMP: N-methylpyrrolidone    -   Tecsol A: product obtained from Eastman Chemicals, composed of        blend of 85.8% ethanol, 9% Isopropanol, 4.2% methanol and 1%        MIBK. Composition numbers were used according to Eastman        information    -   Setalux 17-1450 is an acetoacetate acrylic resin from Nuplex        Resins, 65% s.c. in methyl n-amylketone, with an acetoacetate        equivalent weight of 1150 g/mole.    -   Setalux 26-3701 is an acetoacetate polyester diluent from Nuplex        Resins, 100% solids, with an acetoacetate equivalent weight of        130.

EXAMPLE 1

A formulation was made by the sequential mixing of

-   -   100 g of solution of malonate polyester A-1    -   25 g of Dowanol PMA    -   19.5 g of the catalyst solution C-1    -   67.4 g of acryloyl component B-2 (diTMPTA)        This formulation has a viscosity of 110 mPa·s at a calculated        VOC of 250 g/L. The ratio of malonate-methylenes groups to        acryloyl groups is 1:1.5, the amount of catalyst 0.039 meq/g        solids.

The gel time of this solution was more than 24 hrs. Using a 120-microndoctor blade, the formulation was applied onto glass plates shortlyafter their preparation and subsequently cured at room temperatures toobtain a 85 micron thick clear, colorless and highly glossy films. TNOdust-dry times of less than 30 minutes, and touch-dry times of less than45 minutes were found. Persoz pendulum hardness build-up is given in thetale below:

Days Persoz hardness (secs) 1 62 2 92 9 137 20 148 30 149

Spot tests on these films, cured for 1 month at RT, gave the followingresults.

Contact time and type of solvent Score 5 minutes with xylene 1 1 nightwith water + 2 2 hrs of recovery 1 1 minute with MEK 2

EXAMPLE 2

A formulation was prepared with the following components, as in example1:

-   -   100 g of malonate polyester solution A-2    -   26 g of o-xylene    -   19.0 g of the catalyst solution C-1    -   67.0 g of acryloyol component B-2 (diTMPTA)    -   0.32 g of Byk 310        The catalyst concentration was 0.032 meq/g solids. This        formulation has a calculated VOC of 253 g/L, mole ratio's of the        components similar to example 1. The geltime of the solution was        more than 24 hours. Upon application, as in example 1, and cure        at RT, dust-dry times of less than 30 min, and touch-dry times        of less than 1 hour were found. Persoz hardness build-up of the        film w (65 micron dry) was as follows:

Days Persoz hardness (secs) 1 56 2 99 3 122 9 149 20 170 30 170

Spot tests on the films cured 1 month at RT were carried with thefollowing results:

Contact time and type of solvent Score 5 minutes o-xylene 1 1 night withwater + 2 2 hrs of recovery 1 1 minute MEK 2

EXAMPLE 3

A formulation was made of the following components

-   -   100 g of malonate polyester solution A-2    -   22 g of o-xylene    -   19.0 g of catalyst solution C-1    -   56.0 g of acryloyl component B-2 (DMPTA)        The catalyst concentration was 0.034 meq/g solids. The        formulation has a calculated VOC of 252 g/L., and a gel time of        the solution of more than 24 hrs. Upon application at RT,        dust-dry times of less than 30 min and touch-dry times of less        than 1 hour were found. Persoz hardness (sec) was measured on        films cured under different conditions:

after 10′ flash-off after 10′ flash-off at RT, 30′ at RT, 24′ Ambient @80° C. at 140° C. 1 day 56 170 330 1 month 150 180 —

EXAMPLE 4

Formulations with a solids content of 72 to 75% were made by thesuccessive addition and mixing of the following components

-   -   100 g of malonate polyester solution A-1    -   30 g of Dowanol PMA    -   a certain amount and type of catalyst given in the Table and    -   50.0 g of B-1 (TMPA)        In all formulations, the ratio of malonate-methylene groups to        acryloyl groups was 1:1.26. On glass, 120 micron wet films were        drawn. Results are shown in the table below. It can be seen that        gel times are found in the order of hours, with C-1 excelling        through a pot life of more than 24 hrs. In all cases, dust- and        touch-dry times are short.

Type of catalyst C-4 C-5 C-6 C-7 C-8 C-1 Grams of catalyst 6 7.5 8.4 74.5 15 [cat] in meq/g solids 0.029 0.034 0.037 0.029 0.034 0.029 geltime(hrs) 5 3 4 >>3 6 >24 RT Cure Appearance O.K. O.K. O.K. oozing oozing.O.K. dust dry TNO time (min) 30 30 30 255 60 30 touch-dry TNO time (min)30 45 30 270 120 30 Persoz hardness 1 month 73 65 ND ND 34 57 Stoving10′ @ RT and 30′ @ 140° C. Appearance O.K. O.K. O.K. O.K. O.K. O.K.Persoz hardness 1 day 344 322 270 163 314 325

EXAMPLE 5

Formulations with a solid content of 75% were made by the successiveaddition and mixing of the following components

-   -   100 g of malonate polyester solution A-2    -   amount of Dowanol PMA given in the table    -   a certain amount and type of catalyst given in the Table and    -   56.0 g of B-2 (i.e. di-trimethylolpropane tetraacrylate)        The ratio of malonate-methylene groups to acryloyl groups was        1:1.26. On glass 120 micron wet films were drawn. Both catalysts        give gel times of more than 24 hrs, similar to C-1; C-3 was not        compatible, and curing was insufficient.

Type of catalyst C-2 C-3 Grams of catalyst solution 11.6 26 [cat] inmeq/g solids 0.029 0.029 Dowanol PMA (g) 30 15 geltime (hrs) >24 hrs >24hrs RT Cure Appearance O.K. Sticky dust dry TNO time (min) <60 >24 hrstouch-dry TNO time (min) <60 >24 hrs Persoz hardness 2 days 34 NDStoving 10′ F.O @ RT and 30′ @ 140° C. Appearance O.K. Not O.K. Persozhardness 1 day 280 190

COMPARATIVE EXAMPLES 1 And 2

Formulations (SC 75%) were produced by mixing the parts A and B

Part A: 100 g of malonate polyester solution A-1, 14 g o-xylene, 11.3 gof a 20% solution of DABCO in MEK; Part B: 41.7 g of B-1 TMPTA, 9.3 g(Comp. Ex. 1) or 5.9 g (Comp. Ex. 2) of Setalux 8539BA76 (an epoxyfunctional resin ex Nuplex Resins), 10.5 g of xylene. The ratio ofmethylene groups (in the malonate) versus acrylate groups was 100 to 105equivalents, respectively. 5.0 mole DABCO and 7.8 mole of epoxy groupswere used per 100 mole of methylene groups. for Comp. Ex. 1 and 5.0 moleDABCO and 5.0 mole of epoxy groups were used per 100 mole of methylenegroups for Comp. Ex. 2. On glass 120 micron wet films were drawn andboth cured ambient and by stoving. The results are presented in thefollowing table.

Comparative example 1 2 Mole % DABCO on CH2 (malon) 5 5 Mole % epoxy onCH2 (malon) 7.8 5 geltime (min) 90 135 RT Cure Appearance O.K. Not.O.K.dust dry TNO time (min) 240 Sticky edges touch-dry TNO time (min) 270Sticky edges Persoz hardness after 2 days 134 81 Stoving 10′ F.O @ RTand 30′ @ 140° C. Appearance Yellowish yellowish Persoz hardness 1 day270 190

From the table one concludes that with the DABCO/epoxy catalyst(yielding an in situ formed strong base) the gel time is rather limited,whereas dust- and touch-dry times are clearly longer. Improving drytimes by adding more catalyst will only limit gel times further.Increasing the amount of acryloyl groups did not result in animprovement. Adding some 4-t-butylphenol extended the potlife somewhat,but discoloration of the film occurred after some weeks by exposure todaylight. The DABCO/epoxy system also yields yellowing under stovingconditions.

COMPARATIVE EXAMPLE 3 UP TO 6

A high solid formulation was made by the successive addition and mixingof the following components

-   -   100 g of malonate polyester solution A-1    -   36 g of Dowanol PMA    -   an amount of the catalyst solution given in the table    -   56.0 g of B-2        1.00 or 0.5 equivalent of blocked or free base was applied per        100 equivalents of methylene groups. Films were drawn on glass        with a wet thickness of 120 micron.

Comparative example 3 4 5 6 Type of cat 10% THAH in TBAH-HAc^(a)) TMG inDMC^(b)) DBU solution methanol in PC^(c)) Ámount of solution (g) 14.82.56 2.75 3.65 Mole % on CH2 (malon) 1 0.5  1 1 Gel time 5 minutes  >3days 90 minutes 60 minutes RT Cure Appearance ND Not O.K. Not O.K. O.K.dust dry TNO time (min) >1 day <3 days 90 touch-dry TNO time (min) >1day >3 days 120 Persoz hardness 2 days Tacky tacky 35 Stoving 10′ F.O @RT and 30′ @ 140° C. Appearance ND Severe scorching Not O.K. O.K. Persozhardness 1 day ND Tacky 40 sec ^(a))25% b.w. solution in methanol oftetrabutylammonium hydroxide neutralized with acetic acid; 0.78 mmoleblocked base/g solution ^(b))16.7% b.w. tetramethylguanidine (TMG)dissolved at R.T. in dimethylcarbonate yielding according to titration1.45 meq of unblocked base/g solution ^(c))16.7% b.w.1,8-diazabicyclo[2.2.2.]octane (DBU) dissolved at R.T. inpropylenecarbonate yielding according to titration 1.096 meq ofunblocked base/g solution

From the table it is obvious that the amidine type catalysts TMG or DBUand the unblocked tetrahexylammoniumhydroxide in high solid Real MichaelAddition formulations cannot combine long gel times with short dryingtimes, as the examples according to our invention do. Tetrabutylammoniumblocked with a carboxylic acid as acetic acid yields an excellent geltime but no ambient fast dry, a lot of scorching at stoving conditions,ruining appearance.

EXAMPLE 6 AND 7

Mixed were:

-   -   100 g of malonate polyester solution A-1,    -   Dowanol PMA or o-xylene as given in the Table,    -   an amount of catalyst of C-9 or C-10 as given in the Table    -   67.0 g of B-2        The formulation of both examples had a solid content of 75%. All        films obtained were colorless and highly glossy.

Example 6 7 Type of cat C-9 C-10 Ámount of cat solution (g) 12.5 15.0[cat] in meq/g solids 0.038 0.021 Solvent 33 g of 30 g of o-xyleneDowanol PMA Gel time 8 hrs 4 hrs RT Cure (120 micron wet) AppearanceO.K. O.K. dust dry TNO time (min) <60 minutes <60 minutes touch-dry TNOtime (min) <60 minutes <60 minutes Persoz hardness 2 days (sec) 86 64Persoz hardness 1 month 130 ND Forced drying 10′ @ RT and ND 30′ @80° C.(90 mu wet) Appearance 100 Persoz hardness after 1 day (secs) 110 Persozhardness after 1 month 130 Stoving 10′ F.O @ RT and 30′ @ 140° C. (90micron wet) Appearance ND O.K. Persoz hardness after 1 day (secs) 320 5′Spottest with o-xylene Intact Overnight contact with water Intact

EXAMPLE 8

A formulation was made by the sequential mixing of:

-   -   100 g of malonate polyester solution A-2    -   35 g Dowanol PMA    -   7.5 g of catalyst solution C-11 56.0 g of B-2        The catalyst concentration was 0.025 meq/g solids. The        formulation had a solid content of 75.6%. The geltime of the        formulation was more than 7 hours. Using a 90 micron doctor's        blade, the formulation was applied onto a glass plate and        subsequently, after a flash-off at RT of 10′, cured 24′ at        140° C. resulting in a clear and high glossy film with a Persoz        hardness of 300 sec.

EXAMPLE 9

A formulation with a solid content of 75% was made by the sequentialmixing of

-   -   100 g of malonate polyester solution A-1    -   30 g of Dowanol PMA    -   6 g of C-12    -   50.0 g of A-1(TMPTA)        The catalyst concentration was 0.029 meq/g solids. On glass 120        micron wet films were drawn, to end up colorless, clear and        glossy. Apart from the rather cumbersome preparation with gas of        this blocked catalyst relative to that of the alkylcarbonate        catalysts (see the C-4 catalyst), the tetrabutylammonium        bicarbonate behaves quite well in this high solid formulation.

Tetrabutylammoniumbicarbonate in Type of catalyst: C12 methanol grams ofcatalyst 6 mole % on CH2 (malon) 1 gel time (hrs) 3.5 RT cure AppearanceO.K. dust dry TNO time (min) 30 touch-dry time (min) 30 Persoz hardness1 month 70

EXAMPLE 10

A formulation with a solid content of 75% was made by the successiveaddition and mixing of the following components

-   -   100 g of malonate polyester solution A-1    -   25 g of Dowanol PMA    -   17 grams of C13    -   67.4 g of B-2        The gel time of the formulation (s.c. of 76%) was more than 24        hrs. On glass 90 micron wet films were drawn. All films had TNO        dust and touch-dry times less than 1 hour, and were colorless,        clear and glossy. Persoz hardness was 103 sec after 14 days at        RT. Stoving films for 30′ @ 140° C. yielded a Persoz hardness of        317 secs.

EXAMPLE 11

A formulation was made based on malonate polyester A-1 (100 parts),acryloyl component B-2 (76.8 parts), catalyst solution C14 (12.7 parts),Dowanol PMA (36 parts) to obtain a lacquer with sc 75% and catalystconcentration 0.026 meq/g solids. Water content in this formulation(introduced along with the catalyst solution) was about 0.75 wt %. Thegel time of this formulation was found to be 50 hours. Upon applicationonto glass as discussed in earlier examples, dust-dry and touch-drytimes were evaluated to be less than 15 minutes.

EXAMPLE 12

A series of formulations was made, as described earlier, consisting of:Malonate polyester resin A-1 (9.3 g solids), acryloyl component B-2 7.26g (malonate CH2-acryloyl 1:1.5), and catalyst of type C-4 (to obtain alevel of 0.034 meq/g solids), and diluted with Dowanol PMA to 77% s.c. Asmall amount of water (numbers listed as wt % on total) was added to themixture of catalyst and malonate resin, before the acryloyol componentwas added. The table below details the results for gel time and drying.The results show strikingly that the presence of a small amount waterleads to a very significant improvement of the gel time, whilemaintaining very fast drying characteristics when applied at RT.

code exp. A B C D E F % water in CC 0 0.14 0.3 0.55 1.11 1.36 geltime(h) 2.5 3.5 3.5 4.5 19 33 TNO-drying dust-dry (min.) 15 15 15 15 15 15touch-dry (min.) 30 15 30 30 45 45

EXAMPLE 13

A series of formulations was made, as described in example 12,consisting of: Malonate polyester resin A-1 (9.3 g solids), acryloylcomponent B-2 7.26 g (malonate CH2-acryloyl 1:1.5), and catalyst of typeC-4 (to obtain a varying amount in meq/g solids), diluted with DowanolPMA to 77% s.c. The amount of water added was 1 wt % on totalformulation. The table below details the results for gel time anddrying.

code exp. A B C cat (meq/g solid) 0.034 0.04 0.068 gel time (h) >24h >24 h >24 h TNO-drying (min.) dust dry 15 15 <15 touch dry 30 30 15Persoz hardness after 1 day 65 62 64 after 1 week 116 101 107

It can be seen that the gel time of the systems remains very long, alsoif the amount of catalyst is raised.

EXAMPLE 14

A formulation (75% sc) was prepared, as described above, with malonatepolyester A-1 9 g solids, acryloyl component B-2 6.72 g, catalyst C-13(tetrabutylammonium bicarbonate) at 0.04 meq/g solids, xylene, and anamount of water corresponding to 1 wt % on total. The gel time of thisformulation was more than 72 hrs, with dust-dry and touch dry times of<15 minutes.

EXAMPLE 15

Formulations were prepared as above, with components A-1 and B-2 (ratioas example 13), and an amount of catalyst C-15 so that the catalystconcentration was 0.039 meq/g solids. The formulation with and without 1wt % water were compared: without water, this is 3 hours, with 1 wt %water, it is more than 24 hours.

EXAMPLE 16

Formulations were prepared as above, with components A-1 and B-2 (ratioas example 13), and an amount of catalyst C-16 so that the catalystconcentration was 0.039 meq/g solids. The formulation with and without 1wt % water were compared: without water, this was 5.5 hours, with 1 wt %water, it is more than 24 hours. Drying rates are still fast also in thepresence of water.

EXAMPLE 17 Not According to the Claim

A formulation (66.3% sc) was prepared based on acetoacetate resin A-3(10 g), acryloyl component B-2 (5.8 g), catalyst C-1 (0.04 meq/g solids)and Dowanol PMA. The gel time of this formulation was about 4 hours;upon application as described above, a dust dry time of 60 min wasfound, and a touch-dry time of 105 minutes. Persoz hardness was 276 secafter 3 days at RT.

EXAMPLE 18 Not According to the Claim

Formulations were prepared of acetoacetate resin A-4, acryloyolcomponent B-2, and catalyst C-4 (S.C. 77%, acryloyl to acetoacetateratio 1.5:1, catalyst 0.035 meq/g solids), and a varying amount of water(0, 0.4, 1.1 and 2.0 wt % on total solution). The variation of theamount of water had no significant effect on drying times, nor on geltimes (all around 2.5 hours). No significant beneficial effect of wateron the gel time was observed for these acetoacetate resins, in contrastto the observation for malonate functional resins.

EXAMPLE 19

A formulation (SC 77%) was prepared based on a mixture of two activatedmethylene resins, A-1 (malonate) and A-3 (acetoacetate) in a ratio of9:1 (based on moles activated methylene), acryloyl component B-2 andcatalyst C-4 (0.039 meq/g solids). Results were compared to a similarformulation without the A-3 component, giving the results as follows:

binder malonate-acetoacetate blend malonate only Gel Dust- Touch- GelDust- Touch- wt % water time dry dry time dry dry 0% 2 h 30′ 45′  3-6 h<15′ 15′ 1% 4 h 30′ 45′ >19 h  15′ 30′ binder malonate- acetoacetateMalonate blend only % water in formulation 0% 1% 0% 1% Persoz hardness(sec) 1 105 115 49 53 day

It can be seen that replacing only 10% of malonate functional materialwith acetoacetate functional material, a strong impact is observed, muchmore than is to be anticipated based on the relatively small fraction ofacetoacetate to malonate. Properties typical of the acetoacetate (ashorter gel time, no beneficial effect of water on this), slower drying,built increased hardness for RT cure, are strongly translated into the90-10 blend results. It is believed that this more than proportionaleffect is due to the order of reaction, the more acidic acetoacetatereacting mostly before the less acidic malonates if both have to competefor available base for deprotonation.

The negative impact of the faster reaction of acetoacetate resins in thepot on the gel time and pot life, can be minimized by choosing acomponent of a lower functionality than the A-3 resin used above, to beblended with the malonate resins (viscosity consequences of suchpremature reaction being less)

The next examples illustrate the impact that similar minority components(RMA active, but with lower pKa than malonate) can have on the overallperformance. A significant beneficial impact based on hardness build-up,but also on appearance of these fast-drying systems is observed.

EXAMPLE 20

Formulations (77% SC) were prepared as above, based on malonate resinA-1, acryloyl component B-2 (150% relative to activated CH2), catalystC-4 (at a level of 0.057 meg/g solids). In this series, part of themalonate resin A-1 was substituted for a low molecular weightacetoacetate component, or acetylacetone, so that effectively 10 mole %of the standard malonates were substituted. No water was added. Theresults of the compositions thus obtained are given below.

gel dust touch code SC time dry dry exp. Substitute mole % (%) (h) (min)(min) A None 0 75.0 3.5 10 15 B methyl- 10 76.8 3 20 25 acetoacetate CAATMP 10 76.9 3.5 15 25 D Acetylacetone 10 75.8 6 20 25

Using low functionality substitutes like this, even an improvement inpotlife can be seen in the case of acetylacetone.

code SC film appearance exp. Substitute mole % (%) RT cure 30′ 60° C.30′ 80° C. A None 0 75.0 rough Rough wrinkles B methyl- 10 76.8 smoothsmooth smooth acetoacetate C TMPTAA 10 76.9 smooth acceptable acceptableD Acetylacetone 10 75.8 smooth smooth smooth

For these very fast drying formulations, the substitution of part ofmalonates leads to an improved appearance. Persoz hardness developmentas function of time in days is given in the tables below. Persozhardness in sec

RT cure A B C D time (days) None 10% MeAA 10% TMPTAA 10% AA 0.2 42 99126 1 65 93 117 145 7 139 111 142 162 14 142 106 152 163 21 145 172 28149 107 166 174

It can be seen that despite the introduction of a very soft, lowfunctionality component, the hardness development is not reduced, buteven significantly improved especially in terms of the early hardness.Persoz hardness in sec.

30′ 60 C. cure A B C D time (days) None 10% MeAA 10% AATMP 10% AA 0.0269 207 156 191 1 74 138 137 172 7 91 143 156 177 14 98 136 156 185 21115 187 28 130 131 169 187

For the forced dry conditions, in which after a 10 minute flash-off, a30 minute curing at 60 C was employed, the advantages in hardnessbuild-up are even more evident. At 80 C cure, the advantages become lesspronounced again since the reference formulation already has arelatively high hardness following the high temperature treatment.

Persoz Hardness in Sec.

30′ 80 C. cure A B C D None 10% MeAA 10% AATMP 10% AA 0.02 151 162 194225 1 130 132 191 219 7 147 150 182 228 14 147 144 196 234 21 148 236 28168 142 197 233

Spot tests with xylene also indicate that the introduction of these lowfunctionality components did not lead to reduced solvent resistanceunder the conditions tested, it is even slightly better.

EXAMPLE 21 Not According to the Claim

In this example, the beneficial effect of the substitution of a part ofthe malonate functional groups by a low functionality more acidic CH2functional group component is demonstrated if a catalyst system is usedbased on DABCO-epoxy. The epoxy component used here was Setalux 8503, anepoxy-functional acrylic from Nuplex Resins. The gel time more thandoubles upon addition of 11 C—H equivalent % acetylacetone.

A B Addition None acetylacetone C—H equivalent % moderator 0% 11% mmolemalonate resin A-1 100 100 mmole acryloyol B-1 105 117 mmole epoxy(Setalux 8503) 7.9 8.8 mmole DABCO 5.0 5.6 gel time (SC 72%)  1 h 2.5 hTNO drying times Dust dry 2.5-3.5 h   3-4 h Touch dry >20 h >20 h 

EXAMPLE 22

A pigmented formulation was prepared, in which malonate resin A-1 (167g) was pigmented (using 5.95 g Dysperbyk 2163, 134 Kronos 2310 pigment,0.22 g Byk 370), and formulated with 48.6 grams Dowanol PMA and 122.8 gDMPTA (B-2).

To this base resin, AATMP was added to have a 13 mole % substitution ofmalonate by acetoacetate functions, and 0.04 meg/g solids of a catalystC-4 solution that also contained water, so that the final water contentwas 2 wt % on solids not counting pigment. Solid content of theformulation, not counting the pigments, was 80%. Gel time observed wasmore than 7 hours, dust dry time 15 minutes, touch dry 30 minutes.Appearance of the film was good, with Persoz hardness 82 sec after 5 hrsof drying at RT.

EXAMPLE 23

When lacquer formulations are compared, in which the catalyst solutionis premixed with one of the components, the methylene and acryloylcomponents being mixed later as a 2K systems, it can be observed thatupon standing before mixing, some loss of activity occurs.

In all cases, final formulations were targeted based on malonate resinA-1, DMPTA (B-2) (so that mole ratio acryloyl to malonate is 1.5:1),water to the level of 1 wt % on total, and catalyst C-4 (0.04 meq/gsolids). When water/catalyst and A-1 are premixed, to be blended withB-2 later after a variable amount of time, the following results wereobtained (days=days between premix and total formulation):

Persoz TNO- Hardness drying (sec) dd td 1 day 7 days experiment days geltime (min) (min) RT RT A 0 >24 h  15 30 53 94 B 1 >24 h <30 30 44 87 C2 >24 h  30 45 40 79 D 7 >24 h  >2 h >2 h 19

When catalyst was premixed with the B-2, to be formulated later with A-1in which water was premixed, the following results were obtained:

TNO- Persoz drying Hardness limits (sec) dd td 1 day 7 days experimentdays gel time (min) (min) RT RT E 0 >24 h 15 30 53 94 F 1 >24 h 15 30 52107 G 2 >24 h 15 30 45 102 H 7 >24 h 30 45 47

It can be observed that upon standing, the prolonged exposure of thecatalyst system to the ester components in combination with water, maylead to some loss of reactivity, potentially to some slow hydrolysis ofthe ester groups present, leading to acid that will reduce the amount ofbase that can be effectively generated. This loss of reactivity appearsto be more prominent when premixing is done of the blocked base andwater with the malonate resin, which is known to exhibit a relativelyfast hydrolysis compared to other ester groups.

Therefore, it can be concluded that this system may be best employedeither as a three component system (in which catalyst and both polymercomponents are formulated into a paint as 3 components). When atwo-component system application is desired, it is preferred to employ apremix of activated methylene component and acryloyl component, to beactivated with the catalyst upon final formulation.

EXAMPLE 24

This example illustrates that it is possible to use also urethaneacryloyl compounds in combination with the present catalyst system. Aformulation was made, as described earlier, based on A-1 and B-3(urethane acrylate), in a mole ratio malonate to acryloyl 1:1.5, SC63.5.%, and an amount of catalyst C-4 to end up with 0.028 meq/g solids.Gel time was between 5 and 20 hours, dust-dry and touch-dry times were10 and 15 minutes, respectively. Good MEK spot test results wereobtained for RT cured samples. Persoz hardness (in sec) build-up for theRT cured sample was as follows:

Time (days) Persoz hardness (sec) 0.08 86 0.21 124 1 210 5 300 7 297 14317 28 320

EXAMPLE 25

To test the stability of CO2 blocked catalyst solutions against loss ofCO2, to simulate a situation in which the container of the catalystsolution is left open for an extended time before being closed andre-used later, a solution was prepared of 11.04 g of tetraethylammoniumbicarbonate in 70 grams of methanol. Part of this solution wasintentionally allowed contact with the environment by widely opening thecontainer for an hour. Subsequently, the container was closed again andthe catalyst solution allowed to equilibrate overnight. Similarexperiments were done with the same original solution, to which anaddition 8 grams of DMC was added, and a third set in which on top ofthe DMC, also 8 grams of water was added. After the night ofre-equilibration, these 6 catalyst solutions were added to a standardpremixed formulation of 100 parts of A-1, 77 parts of B-2, 30 parts ofxylene and 12 part of Dowanol PMA (nominally 0.05 meq/g solids). Geltimes were tested: In both cases without water, a reduction in gel timewas observed from approximately 5 to <3 hours, following leaving thecatalyst container open. The catalyst solution that contained both DMCas well as water, maintained a very long gel time (>24 hrs) when used ina paint, also after having the container left open. It is believed thatthe combination of DMC and water allows any strong base species beingformed unintentionally by premature CO2 evaporation to be reformed toblocked methocarbonates. The impact of solvent type and level isillustrated in the following examples.

EXAMPLE 26

Paints were formulated as follows (amounts in gr), with a blocked basecatalyst concentration at 0.04 meq/g solids:

Example A-5 24.00 Example A-6 1.00 Example B-4 4.63 TMPTA 3.84 CatalystC-17 1.37

To this formulation was added additional solvent to lower solids contentto 51%. The composition of the solvent in paints M1 to M6 (in wt % tototal composition) are described in the Table below.

Description water DMC BuAc xylene MPK NMP Ethanol methanol MIBK2-propanol M1 Tecsol A 0.90 0.70 2.42 8.73 31.48 1.58 0.33 3.37 M2 50/500.90 0.70 2.42 8.73 18.35 15.74 0.79 0.17 1.71 Tecsol A/MPK M3 25/750.90 0.70 2.42 8.73 27.52 7.87 0.40 0.08 0.89 Tecsol A/MPK M4 10/90 0.900.70 2.42 8.73 33.04 3.13 0.16 0.03 0.39 Tecsol A/MPK M5 MPK 0.90 0.702.42 8.73 36.69 0.06 M6 80/20 0.90 0.70 2.42 8.72 7.34 25.20 1.26 0.262.71 Tecsol A/NMP

The viscosity rise in a closed tube was evaluated over time (time inminutes, viscosity in centipoises) using Gardner-Holt bubble tubes. Themeasurement results are indicated in the Table below.

It can be seen that the addition of Tecsol A (major component beingethanol), even to levels as low as 3% on total (M4), significantlyreduces the rate of viscosity rise compared to a cosolvent compositionconsisting mainly of esters, aromatics and ketones and thereforeimproves pot life. In all these case, drying remained fast, dry-throughtimes of 15 minutes or less.

M1 M2 M3 M4 M5 M6 TIME Viscosity TIME Viscosity TIME Viscosity TIMEViscosity TIME Viscosity TIME Viscosity 0 22 0 12.5 0 12.5 0 12.5 0 12.50 22 60 22 36 12.5 29 12.5 20 12.5 5 12.5 8 22 104 22 80 12.5 73 12.5 6412.5 49 12.5 54 22 128 22 104 12.5 97 12.5 88 12.5 73 12.5 78 22 255 22231 12.5 224 12.5 215 12.5 200 12.5 205 22 400 22 376 12.5 369 12.5 36012.5 345 22 350 22 1459 22 1435 12.5 1428 12.5 1419 12.5 1404 800 140922 1868 22 1844 12.5 1837 12.5 1828 12.5 1818 22 2855 22 2831 12.5 282412.5 2815 22 2805 22 3271 22 3247 12.5 3240 12.5 3231 32 3221 22 4514 224490 12.5 4483 12.5 4474 50 4464 22 7905 27 7881 12.5 7874 12.5 7865 3557855 22

EXAMPLE 27

In another set of experiments, we compared different types of alcoholswith respect to their impact on pot life. A starting formulation wasprepared with the following composition, and catalyzed with blocked baseat a level of 0.04 meq/g solids:

Example A-7 25.00 TMPTA 8.12 Example B-4 9.79 Catalyst C-17 1.81

This paint was reduced with various solvents to a 62% SC, to have thefollowing overall solvent compositions (amounts in wt % on totalcomposition):

Descrip- DEG- p-amyl diacetone n-but- 2-prop- n-prop- tion water DMC MAKBG MPK BuAc BE alcohol alcohol anol ethanol methanol MIBK anol anol N1MPK 1.1 0.85 6.50 25.3 4.76 0.08 N2 Tecsol A 1.1 0.85 6.48 4.75 21.9 1.10.2 2.438 N3 Isoprop- 1.1 0.85 6.50 4.76 25.4 anol N4 Diethylene 1.10.85 6.50 4.76 25.3 0.08 Glycol Butyl Ether N5 n-Butanol 1.1 0.85 6.504.76 25.3 0.08 N6 p-Amyl 1.1 0.85 6.50 4.76 25.3 0.08 Alcohol N7Diacetone 1.1 0.85 6.50 4.76 25.3 0.08 alcohol N8 Butyl 1.1 0.85 6.5025.3 4.76 0.08 Glycol N9 n-propanol 1.1 0.85 6.48 4.75 25.6

The viscosity development in a closed tube was determined, as istabulated below (time in minutes, viscosity in centipoise). It can beseen that short chain primary alcohol cosolvents as Tecsol-A (maincomponent ethanol), n-propanol, 1-butanol, amyl alcohol and butyl glycolare very effective in prolonging the pot life of this system,isopropanol being of lower effectivity, but still higher than methylpropyl ketone, diethylene glycol butyl ether and diacetone alcohol. Inall cases, drying remained fast (maximum dry through times 37 minuteswhen applied at 50 mu dry film thickness, and cured at RT).

N1 N2 N3 N4 N5 TIME Viscosity TIME Viscosity TIME Viscosity TIMEViscosity TIME Viscosity 0 27 0 27 0 41 0 152.5 0 41 49 27 37 27 123 4189 165 17 50 146 41 134 27 169 41 134 182.5 122 50 192 41 179 27 233 41198 182.5 186 50 256 41 243 27 284 50 250 182.5 238 57.5 307 75 295 27337 50 310 200 290 57.5 360 75 348 27 367 50 333 200 318 57.5 390 85 37827 421 65 386 220 373 65 444 92.5 432 41 1392 100 1358 340 1346 75 1415800 1402 41 1544 112.5 1510 340 1507 75 1555 41 1665 112.5 1630 355 162875 1675 41 1901 125 1871 480 1860 75 1968 41 2822 182.5 2778 75 2886 412984 200 2883 85 3051 41 3218 200 3118 92.5 3286 41 4252 400 4149 1004318 41 4490 112.5 4658 41 8630 125 8844 65 10310 140 10524 65 11570 14511784 65 N6 N7 N8 N9 TIME Viscosity TIME Viscosity TIME Viscosity TIMEViscosity 0 75 0 125 0 41 81 75 51 132.5 24 41 202 75 172 182.5 41 41269 75 239 182.5 64 41 364 75 334 182.5 92 41 435 75 407 200 123 41 135175 1328 490 169 41 1517 85 1490 490 237 41 1752 92.5 1723 590 325 412783 100 378 41 3124 112.5 439 41 7285 132.5 1407 57.5 8965 165 10225230

EXAMPLE 28 Not According to the Claim

The pot life extending effect of these alcoholic cosolvents also worksfor acetoacetate-acrylate based compositions with the present catalystsystem. This in illustrated with the data below. The system wascatalyzed with 0.04 meq blocked base/g solids.

Setalux 17-1450 22.00 Setalux 26-3701 3.00 TMPTA 6.14 Catalyst C-17 1.17

This mixture was reduced to a 55% sc with various cosolvents, to obtainthe following cosolvent levels.

Aromatic 2- Description water DMC MAK BG MPK BuAc 100 ethanol methanolMIBK propanol P1 Tecsol A 0.71 0.56 18 22.12 1.10 0.23 2.32 P2 50/500.71 0.56 18 13.2 11.06 0.55 0.11 0.80 Tecsol A/MPK P3 25/75 0.71 0.5618 19.3 5.53 0.28 0.06 0.58 Tecsol A/MPK P4 MPK 0.71 0.56 18 25.7 0.05P5 Butyl 0.71 0.56 18 25.7 0.05 Glycol P6 n-Butyl 0.71 0.56 18 25.7 0.05Acetate P7 Aromatic 0.71 0.56 18 25.7 0.05 100

The viscosity (Visco) increase in time (T) in a closed tube was measured(time in minutes, viscosity in centipoises).

P1 P2 P3 P4 P5 P6 P7 T Visco T Visco T Visco T Visco T Visco T Visco TVisco 0 85 0 57.5 0 57.5 0 65 0 165 0 75 0 112.5 60 85 51 57.5 44 57.536 100 26 182.5 17 75 8 112.5 87 85 78 57.5 71 57.5 63 495 53 200 45152.5 35 132.5 114 85 105 65 98 65 90 800 79 200 71 630 64 225 148 85139 65 132 75 113 262.5 95 500 180 85 171 75 164 132.5 145 262.5 119 800244 92.5 235 85 227 340 208 490 286 100 277 100 270 800 222 495 332112.5 323 152.5 251 590 394 132.5 385 237.5 446 140 437 490

The pot life of these acetoacetate systems is much more critical thanfor the malonate systems. Still, it can be observed that primaryalcohols as butyl glycol, but especially the use of Tecsol-A (ethanolbeing the major component) gives a significant retardation of viscositybuild-up, even at levels as low as 5 wt % ethanol.

EXAMPLE 29

The impact of additional alcoholic cosolvents was also demonstrated whenusing a methanolic starting catalyst composition C-18. A startingformulation was prepared with the following composition, and catalyzedwith blocked base at a level of 0.04 meq/g solids:

Example A-7 25.00 TMPTA 8.12 Example B-4 9.79 Catalyst C-18 2.9

The paint was reduced with various solvents to a solids content of 60%.Estimated cosolvent composition is given in the following table (wt % ontotal composition).

p- DEG- amyl diacetone n- 2- Description DMC MAK BG MPK BuAc BE alcoholalcohol butanol ethanol methanol MIBK propanol NMP K1 Methyl 2.3 6.325.11 4.6 1.72 propyl ketone K2 Tecsol A 2.3 6.3 4.6 21.54 2.80 0.232.26 K3 Isopropanol 2.3 6.3 4.6 1.72 25.1 K4 Diethylene 2.3 6.3 4.6 25.11.72 Glycol Butyl Ether K5 n-Butanol 2.3 6.3 4.6 25.11 1.72 K6 p-Amyl2.3 6.3 4.6 25.11 1.72 Alcohol K7 Diacetone 2.3 6.3 4.6 25.11 1.72alcohol K8 Butyl 2.3 6.3 25 4.6 1.72 Glycol K9 NMP 2.3 6.3 4.6 1.72 25.1K10 MAK 2.3 31.4 4.6 1.72

The viscosity development in a closed tube was followed, and isrepresented below (time in minutes, viscosity in centipoises). It can beseen that, the presence of additional primary alcohols as ethanol,n-butanol, n-amyl alcohol and butylglycol is clearly advantageous inreducing viscosity build-up relative to the use of other solvents,despite all formulations already having a level of 2 wt methanolinherited from the catalyst solution.

K1 K2 K3 K4 K5 TIME Viscosity TIME Viscosity TIME Viscosity TIMEViscosity TIME Viscosity 0 22 0 22 0 32 0 92.5 0 41 53 22 43 22 34 32 2092.5 70 41 118 22 108 22 100 32 85 100 143 41 190 22 180 22 172 32 157100 198 41 246 22 237 22 228 41 217 100 257 41 309 22 300 27 288 50 277112.5 324 41 375 27 366 27 354 50 343 112.5 393 41 445 27 435 27 423 50421 112.5 1365 65 1417 57.5 1408 27 1395 132.5 1386 132.5 1561 65 160785 1598 27 1591 132.5 1575 152.5 1687 75 1732 85 1723 27 1715 152.5 1701152.5 1821 75 1868 100 1859 27 1851 182.5 1837 152.5 2792 85 2841 2752832 41 2824 330 2811 200 3005 85 3050 435 3042 41 3034 400 3020 200 K6K7 K8 K9 K10 TIME Viscosity TIME Viscosity TIME Viscosity TIME ViscosityTIME Viscosity 0 50 0 75 0 65 0 85 0 27 54 50 48 75 76 65 51 140 42 27126 50 120 75 135 65 110 225 95 27 182 50 178 75 195 65 170 330 155 27241 50 238 85 261 65 236 880 221 27 307 50 305 85 339 75 291 32 377 50382 85 1305 85 1264 112.5 1351 85 1348 132.5 1496 85 1460 112.5 1547 851539 140 1625 92.5 1589 132.5 1673 85 1667 152.5 1755 92.5 1719 132.51807 85 1799 152.5 2731 112.5 2695 330 2782 112.5 2774 200 2940 112.52904 470 2991 112.5 2983 212.5

What is claimed is:
 1. A crosslinkable polymer composition comprisingreactive components A and B each comprising at least 2 reactive groupswherein the at least 2 reactive groups of component A are acidic protons(C—H) in activated methylene or methine groups and the at least 2reactive groups of component B are activated unsaturated groups (C═C) toachieve crosslinking by Real Michael Addition (RMA), wherein thecomponent A is a malonate containing component and wherein components Aand B react on drying of the crosslinkable polymer composition bydeblocking of latent base catalyst C by evaporation of carbon dioxide,which latent base crosslinking catalyst, is a substituted carbonate saltaccording to formula 1

wherein X⁺ represents a non acidic cation and wherein R is hydrogen,alkyl, aryl or aralkyl group.
 2. The crosslinkable composition accordingto claim 1, wherein the component A or B or both each independently area polymer, oligomer, dimer or monomer molecule and wherein at least oneof components A, B and C are on separate molecules or combined in one ormore molecules.
 3. The crosslinkable composition according to claim 1wherein the malonate component A is an oligomer or polymer wherein thepolymer comprises a polyester, polyurethane, polyether, polyacrylic orpolycarbonate or mixtures, blends or hybrids thereof.
 4. Thecrosslinkable composition according to claim 1, wherein the component Bcomprises two or more unsaturated acryloyl, maleate, methacryloyl orfumarate functional groups.
 5. The crosslinkable composition accordingto claim 1, wherein the malonate component A comprises a number averageof 2 to 20 reactive acidic protons (C—H).
 6. The crosslinkablecomposition according to claim 1, wherein the ratio of the number ofacidic protons (C—H) in malonate component A to the number of activatedunsaturated groups (C═C) on component B is in the range between 10 and0.1.
 7. The crosslinkable composition according to claim 1, comprisingin addition to the malonate component A, a second component A2comprising reactive acidic protons having a higher acidity thancomponent A and also is reactive towards component B.
 8. Thecrosslinkable composition according to claim 7, wherein the secondacidic component A2 is a C—H acidic component reactive towards componentB with an RMA reaction.
 9. The crosslinkable composition according toclaim 8, wherein the second acidic component A2 is an activatedmethylene compound according to formula 2

wherein R is hydrogen or an alkyl, aralkyl or aryl substituent and Y andY′ are same or different substituent groups, or wherein at least one ofthe —C(═O)—Y and —C(═O)—Y′ is replaced by CN or phenyl and wherein A2has higher acidity than malonate by choice of at least one of: adifferent R, a different Y, and a different Y′.
 10. The crosslinkablecomposition according to claim 9 wherein component A2 is an acetoacetateor acetylacetone containing component.
 11. The crosslinkable compositionaccording to claim 7, wherein the pKa of component A2 is between 0.5 and6 units lower than the pKa of malonate component A.
 12. Thecrosslinkable composition according to claim 7, wherein the amount ofreactive acid protons in component A2 is between 0.1 and 50 mole % ofthe total mole of reactive acid protons in components A and A2.
 13. Thecrosslinkable composition according to claim 7, wherein the reactive C—Hfunctionality of component A2 is lower than the C—H functionality ofmalonate component A.
 14. The crosslinkable composition according toclaim 1, comprising an organic solvent wherein at least part of thesolvent is an primary alcohol wherein the alcohol is present in anamount of at least 1 and at most 45 wt % relative to the total weight ofthe crosslinkable composition and wherein the alcohol is a primarymono-alcohol having 1-20 carbon atoms.
 15. The crosslinkable compositionaccording to claim 14, wherein the alcohol is a primary mono-alcoholhaving 1 to 20 carbon atoms.
 16. The crosslinkable composition accordingto claim 1, further comprising 0.1-10 wt % of water (relative to totalweight of the crosslinkable composition).
 17. The crosslinkablecomposition according to claim 1, comprising the latent crosslinkingcatalyst in an amount ranging between 0.001 and 0.3 meq/g solids (meq/gsolids defined as moles latent base relative to the total dry weight ofthe crosslinkable composition).
 18. The crosslinkable compositionaccording to claim 1, wherein the cation in the latent crosslinkingcatalyst is a quaternary ammonium or phosphonium carbonate saltaccording to formula 3,

wherein Y represents N or P, and wherein: each R′ is a same or differentalkyl, aryl or aralkyl group or a polymer, R is hydrogen, alkyl, aryl oraralkyl group or a polymer, or a bridged ring structure with R′.
 19. Thecrosslinkable composition according to claim 1 in the form of a set ofseparate unmixed precursor compositions wherein one precursorcomposition comprises components A and B and another precursorcomposition comprises the latent crosslinking catalyst composition. 20.The crosslinkable composition according to claim 1, wherein thecrosslinkable components in the composition are a binder in a coatingcomposition, further comprising one or more coating additives.
 21. Thecrosslinkable composition according to claim 20, having a solids contentbetween 55 and 100% and 0 to 45 wt % solvent having a dry to touch timeat room temperature between 5 to 120 min and a gel time of at least 3hours at room temperature.
 22. Coating layers comprising a cured coatingcomposition according to claim 20.